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Stem cells in platelet-rich plasma (PRP) scaffolds may be a promising treatment for cartilage repair. Human dental pulp stem cell (hDPSC) subpopulations have been identified to have substantial angiogenic, neurogenic and regenerative potential when compared with other stem cell sources. The present study evaluated the potential of hDPSCs in a PRP scaffold to regenerate full-thickness cartilage defects in rabbits. Full-thickness articular cartilage defects were created in the patellar groove of the femur of 30 rabbits allocated into three experimental groups: Those with an untreated critical defect (CTL), those treated with PRP (PRP) and those treated with stem cells in a PRP scaffold (PRP+SC). The patellar grooves of the femurs from the experimental groups were evaluated macroscopically and histologically at 6 and 12 weeks post-surgery. The synovial membranes were also collected and evaluated for histopathological analysis. The synovial lining cell layer was enlarged in the CTL group compared with the PRP group at 6 weeks (P=0.037) but not with the PRP+SC group. All groups exhibited low-grade synovitis at 6 weeks and no synovitis at 12 weeks. Notably, macroscopic grades for the area of articular cartilage repair for the PRP+SC group were significantly improved compared with those in the CTL (P=0.001) and PRP (P=0.049) groups at 12 weeks. Furthermore, histological scores (modified O'Driscoll scoring system) of the patellar groove articular cartilage in the PRP+SC and PRP groups, in which the articular cartilage was primarily hyaline-like, were significantly higher compared with those in the CTL group at 12 weeks (P=0.002 and P=0.007, respectively). The present results support the therapeutic use of hDPSCs for the treatment of full-thickness articular cartilage defects.
ABSTRACT
ABSTRACT Background: Hematologic neoplasms are associated with mutations in hematopoietic cells and chromosomal abnormalities. During aging, about 2-3% of the elderly have chromosomal abnormalities arising from clonal mosaicism, the immune system is impaired and the bone marrow loses its ability to replace blood cells. Objective: To describe the epidemiological and cytogenetic profile of hematological malignancies, highlighting the frequency of chromosomal alterations in these neoplasms associated with aging. Method: A retrospective cross-sectional study with analysis of karyotype exams results was performed in the Cytogenetic Laboratory of thee Blood Center of the Faculdade de Medicina de Marilia (FAMEMA) between 1998 and 2016. Blood samples from child and adult patients with different hematological malignancies treated in the Onco-hematology Outpatient Clinics of the local blood center and hospitals, and external clinics were tested. Results: Karyotype exam results of 746 patients with a mean age of 54.7 years (±23.1) were analyzed. The elderly had the highest frequency of hematological malignancies (50.9%), followed by adults (38.3%) and young people (10.7%); elderly women had the highest percentage (55.0%). Normal karyotypes (46,XX/46,XY) were more common (61.8%) compared to abnormal karyotypes, especially among the elderly (56.4%). Myeloproliferative neoplasms were an exception with 67.4% of abnormal karyotypes. Conclusion: There is a higher frequency of hematological malignancies among the elderly. It is possible to conclude that failures in genomic mechanisms and hematopoiesis with aging lead to the formation of cells with the chromosomal alterations found in hematological malignancies.
Subject(s)
Humans , Male , Female , Infant, Newborn , Infant , Child, Preschool , Child , Adolescent , Adult , Middle Aged , Aged , Aged, 80 and over , Aging , Epidemiology , Chromosome Aberrations , Hematologic Neoplasms/epidemiologyABSTRACT
BACKGROUND: Hematologic neoplasms are associated with mutations in hematopoietic cells and chromosomal abnormalities. During aging, about 2-3% of the elderly have chromosomal abnormalities arising from clonal mosaicism, the immune system is impaired and the bone marrow loses its ability to replace blood cells. OBJECTIVE: To describe the epidemiological and cytogenetic profile of hematological malignancies, highlighting the frequency of chromosomal alterations in these neoplasms associated with aging. METHOD: A retrospective cross-sectional study with analysis of karyotype exams results was performed in the Cytogenetic Laboratory of thee Blood Center of the Faculdade de Medicina de Marilia (FAMEMA) between 1998 and 2016. Blood samples from child and adult patients with different hematological malignancies treated in the Onco-hematology Outpatient Clinics of the local blood center and hospitals, and external clinics were tested. RESULTS: Karyotype exam results of 746 patients with a mean age of 54.7 years (±23.1) were analyzed. The elderly had the highest frequency of hematological malignancies (50.9%), followed by adults (38.3%) and young people (10.7%); elderly women had the highest percentage (55.0%). Normal karyotypes (46,XX/46,XY) were more common (61.8%) compared to abnormal karyotypes, especially among the elderly (56.4%). Myeloproliferative neoplasms were an exception with 67.4% of abnormal karyotypes. CONCLUSION: There is a higher frequency of hematological malignancies among the elderly. It is possible to conclude that failures in genomic mechanisms and hematopoiesis with aging lead to the formation of cells with the chromosomal alterations found in hematological malignancies.
ABSTRACT
BACKGROUND: Recently, the importance of cytogenetics has grown in the diagnosis, prognosis and treatment of leukemias and myelodysplastic syndromes. 5-azacytidine is a drug that has well-known cytogenetical effects and is approved in the treatment of myelodysplastic syndromes. To date, no studies have been performed to evaluate the impact of 5-azacytidine on the chromosomes of patients with hematological neoplasias. This study aimed to investigate the effects of 5-azacytidine on chromosomes of patients with different hematological malignancies using G-band analyses to identify possible cytogenetical alterations. METHODS: The peripheral blood of 18 patients with hematological malignancies and 18 controls was collected in heparinized tubes. 5-azacytidine was added, at a final concentration of 10-5M, to cultures 7 hours prior to harvest. RESULTS: Uncoiled centromeric/pericentromeric heterochromatin of chromosomes-1, 9 and 16 occurred more frequently in the patients than in controls. This higher frequency of uncoiled heterochromatin was statistically significant (p-value = 0.004) for chromosome-9. Conversely, we observed that the fragile site at 19q13 was more frequent in controls (p-value = 0.0468). CONCLUSIONS: The results of this study suggest that satellite sequences, located in the heterochromatin of chromosome-9, are hypomethylated in hematological malignancies. This hypomethylation may contribute to the disease, activating transposable elements and/or promoting genomic instability, enabling the loss of heterozygosity of important tumor suppressor genes. An investigation of the 19q13 region may help to understand whether or not the predominant occurrence of the fragile site at 19q13 in controls is due to hypermethylation of this region.
Subject(s)
Humans , Male , Female , Azacitidine/adverse effects , Cytogenetic Analysis , Hematologic Neoplasms , Heterochromatin , Leukemia , Myelodysplastic SyndromesABSTRACT
BACKGROUND: Recently, the importance of cytogenetics has grown in the diagnosis, prognosis and treatment of leukemias and myelodysplastic syndromes. 5-azacytidine is a drug that has well-known cytogenetical effects and is approved in the treatment of myelodysplastic syndromes. To date, no studies have been performed to evaluate the impact of 5-azacytidine on the chromosomes of patients with hematological neoplasias. This study aimed to investigate the effects of 5-azacytidine on chromosomes of patients with different hematological malignancies using G-band analyses to identify possible cytogenetical alterations. METHODS: The peripheral blood of 18 patients with hematological malignancies and 18 controls was collected in heparinized tubes. 5-azacytidine was added, at a final concentration of 10-5M, to cultures 7 hours prior to harvest. RESULTS: Uncoiled centromeric/pericentromeric heterochromatin of chromosomes-1, 9 and 16 occurred more frequently in the patients than in controls. This higher frequency of uncoiled heterochromatin was statistically significant (p-value = 0.004) for chromosome-9. Conversely, we observed that the fragile site at 19q13 was more frequent in controls (p-value = 0.0468). CONCLUSIONS: The results of this study suggest that satellite sequences, located in the heterochromatin of chromosome-9, are hypomethylated in hematological malignancies. This hypomethylation may contribute to the disease, activating transposable elements and/or promoting genomic instability, enabling the loss of heterozygosity of important tumor suppressor genes. An investigation of the 19q13 region may help to understand whether or not the predominant occurrence of the fragile site at 19q13 in controls is due to hypermethylation of this region.
ABSTRACT
As células-tronco apresentam uma alta capacidade de autorregeneração, assim como, um potencial de diferenciação em uma variedade de tipos celulares. Estas células podem ser classificadas como embrionárias e adultas. Apesar de apresentar propriedades de células-tronco, as mesenquimais apresentam um certo grau de dificuldade no estabelecimento das culturas, podendo induzir a perda da expressão da enzima responsável pela imortalização ou enzima telomerase. A enzima telomerase é considerada um relógio biológico, um indicador que a senescência celular irá se instalar inevitavelmente. A questão mais atual e intrigante dos pesquisadores é se o suposto potencial de divisão, por um determinado período de tempo, das células-tronco cultivadas poderia levar ao acúmulo de alterações genéticas e epigenéticas, resultando em um processo neoplásico. Daí a importância do papel da citogenética humana no controle e monitoramento das células-tronco cultivadas que serão utilizadas na terapia em seres humanos. Alterações cromossômicas estruturais, tais como deleções, translocações e inversões, representam um mecanismo importante pelo qual as células cancerígenas desenvolvem-se gradualmente, uma vez que estas alterações cromossômicas podem levar a uma expressão anormal de muitos genes, podendo desencadear assim o processo neoplásico.
Stem cells have a high capacity of self-regeneration, as well as a potential to differentiate into several cell types. These cells can be classified as embryonic or adult. In spite of having inherent properties of stem cells, mesenchymal cells show a certain degree of difficulty to establish cultures. This might induce a loss of the expression of the telomerase enzyme which is considered to be a biological clock or an indicator of the senescence of the cells. The most current and intriguing question for researchers is whether the presumed division potential of cultivated stem cells, over a period of time could result in an accumulation of genetic alterations and consequently, in a neoplastic process. For this reason, cytogenetic techniques are very important to guarantee the control and safety of cultivated stem cells to be used in human therapy. Structural chromosomal alterations, such as for example, deletions, translocations and inversions represent an important mechanism by which cells might gradually transform in a neoplastic process. Thus, these chromosomal alterations could result in an abnormal expression of the genes and lead to cancer.